Vegetable Production & Nutritional Content in Season-Extension Systems; Gardening Guidebook for Wyoming ~ University of Wyoming ~ For more information, Please see websites below: ` Organic Edible Schoolyards & Gardening with Children = http://scribd.com/doc/239851214 ~ ` Double Food Production from your School Garden with Organic Tech = http://scribd.com/doc/239851079 ~ ` Free School Gardening Art Posters = http://scribd.com/doc/239851159 ~ ` Increase Food Production with Companion Planting in your School Garden = http://scribd.com/doc/239851159 ~ ` Healthy Foods Dramatically Improves Student Academic Success = http://scribd.com/doc/239851348 ~ ` City Chickens for your Organic School Garden = http://scribd.com/doc/239850440 ~ ` Huerto Ecológico, Tecnologías Sostenibles, Agricultura Organica http://scribd.com/doc/239850233 ` Simple Square Foot Gardening for Schools - Teacher Guide = http://scribd.com/doc/239851110

1. RJ-217
May 2012
Karen L. Panter and Adrienne O. Tatman
Vegetable Production
and Nutritional Content in
Season-Extension Systems

2. Vegetable Production and Nutritional
Content in Season-Extension Systems
Authors:
Karen L. Panter, Extension Horticulture Specialist, Department of Plant Sciences
Adrienne O. Tatman, former Research Associate, Sheridan Research and Extension Center
Issued in furtherance of extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. De-
partment of Agriculture. Glen Whipple, director, University of Wyoming Extension, University of Wyoming,
Laramie, Wyoming 82071.
Persons seeking admission, employment, or access to programs of the University of Wyoming shall be consid-
ered without regard to race, color, religion, sex, national origin, disability, age, political belief, veteran status,
sexual orientation, and marital or familial status. Persons with disabilities who require alternative means for
communication or program information (Braille, large print, audiotape, etc.) should contact their local UW
Extension office. To file a complaint, write to the UW Employment Practices/Affirmative Action Office, Univer-
sity of Wyoming, Department 3434, 1000 E. University Avenue, Laramie, WY 82071.
Editor: Robert Waggener, Waggener Editorial Services, Laramie, Wyoming
Graphic Designer: Bernadette van der Vliet, College of Agriculture and Natural Resources, Office of
Communications and Technology
Funds for this project were provided through the Wyoming Department of Agriculture and the USDA’s
Specialty Crop Block Grant Program

3. Funded by a Wyoming Department of
Agriculture Specialty Crop Block Grant
Program grant, the overall goal of this proj-
ect was to develop and promote sustainable
specialty horticultural practices for Wyoming.
The specific objective was to evaluate several
vegetable crops for yield and nutritional content
using different fertilization levels. Basic yields
as well as nutritional information gained from
laboratory analyses of total phenols, total flavo-
This bulletin describes one part in a series of three projects conducted in 2009 and 2010 at
the University of Wyoming’s Sheridan Research and Extension Center. Peppers, tomatoes,
and eggplants were grown both years in the field, in a high tunnel, or under row covers. Yields
of each plant type were recorded, and total phenols, total flavonoids, and antioxidants were
determined at the University of Nebraska-Lincoln’s Small Molecule Analysis Lab. Results of
yields and nutritional status depended on plant type and whether the plants were grown in the
field, in a high tunnel, or under row covers. Tables of yield data and graphs of nutritional con-
tents are included.
noids, and antioxidant activity will be valuable
to vegetable producers and consumers alike.
Nutritional parameters of total flavonoids, total
phenols, and antioxidants were assessed as
these are important in overall human health.
Flavonoids, naturally occurring compounds
found in many plants, number more than 4,000.
They can be found in many fruits, vegetables,
and beverages including cranberry, apple,
peanut, chocolate, onion, tea, and red wine.
3

4. Flavonoids have antioxidant activity, meaning they help neutralize free radicals (Cleveland Clinic,
2011), which can cause cancer and contribute to the aging process. Flavonoids act against cardiovascu-
lar diseases, ulcers, viruses, arthritis, and other ailments (Patel, 2008). Phenols are strong antioxidants
as well, preventing free radical damage and decreasing chances of cancer and cardiovascular disease
(Hollman, 2001). Antioxidants in general, as measured by oxygen radical absorbance capacity, are
known to help eliminate free radicals from the body. Antioxidants can be found in a large variety of
fruits, nuts, and vegetables (Nutrient Data Laboratory, 2007).
Trials of several varieties of tomatoes, peppers, beets, and carrots were grown to compare gen-
eral performance, yield, and nutritional content under different fertilization schemes. Vegetables were
planted at the University of Wyoming’s Sheridan Research and Extension Center (ShREC), seven
miles east of Sheridan, Wyoming, in May 2009 and May 2010. Transplants of tomatoes and peppers
were used, and carrots and beets were direct-seeded into the plots.
4

5. Activities Performed and Outcomes
2009 Season-Extension Yields
Peppers, tomatoes, and eggplants were grown in a high tunnel, under row covers, or in the
field during the summer of 2009 in the organic production plots at the University of Wyo-
ming’s Sheridan Research and Extension Center (ShREC).
Five plants of each of these varieties were planted May 20 in each location:
Peppers: ‘King of the North’, ‘Purple Beauty’
Tomatoes: ‘Rutgers’, ‘Cosmonaut’
Eggplants: ‘Black Beauty’, ‘Turkish Orange’
These varieties were chosen because they had been successfully grown before at the
ShREC and because of their ease of propagation from seeds. Plants were irrigated as needed
during the growing season. No additional fertilizer was added. The production areas used in
this study are in the process of gaining organic certification. Since organic matter and other
natural sources of fertilizer have been incorporated over the last several years, no additional
fertilization was deemed necessary in 2009.
Pepper yields:
Peppers 2009 (5 plants per location)
Total yield (g)
Cultivar Field High tunnel Row cover
King of the North 2,863 2,638 4,853
Purple Beauty 1,508 1,690 1,944
Yields of both pepper cultivars were highest under row covers. Lowest yields occurred in
the high tunnel with ‘King of the North’ and in the field with ‘Purple Beauty’.
Tomato yields:
Tomatoes 2009 (5 plants per location)
Total yield (g)
Cultivar Field High tunnel Row cover
Rutgers 20,865 15,581 17,112
Cosmonaut 15,846 14,082 7,796
Yields of tomatoes depended on location. Both varieties produced the most fruit in the
field. ‘Rutgers’ produced the least amount of fruit in the high tunnel, while ‘Cosmonaut’ pro-
duced the least under the row cover.
5

6. Eggplant yields:
Eggplant 2009 (5 plants per location)
Total yield (g)
Cultivar Field High tunnel Row cover
Black 1,595 2,465 972
Turkish Orange 210 281 0
Neither variety of eggplant produced much fruit. Both yielded the most under the high tunnel,
while ‘Turkish Orange’ yielded zero under the row cover.
2010 Season-Extension Yields
As in 2009, two varieties each of peppers, tomatoes, and eggplants were grown either in the field,
under row cover, or in a high tunnel. Five plants of each variety were planted June 1. They included:
Peppers: ‘King Crimson’, ‘California Wonder Orange’
Tomatoes: ‘Rutgers’, ‘Cosmonaut’
Eggplant: ‘Black Beauty’, ‘Turkish Orange’
Plants were irrigated as needed. Fertilizer was applied six times during the growing season using
Drammatic® “O” organic fish and kelp fertilizer (2-5-0.2) at a rate of 1 tablespoon per gallon of water,
with about 1 gallon of solution applied per plant per fertilization. Plants were fertilized in 2010 as it
was thought that yields might be boosted in all three growing locations with additional nutrients.
6

7. Pepper yields:
Peppers 2010 (5 plants per location)
Total yield (g)
Cultivar Field High tunnel Row cover
King Crimson 201 195 35
California Wonder Orange 116 1,326 182
‘California Wonder Orange’ had the highest yields in the high tunnel and lowest in the field.
Yields of ‘King Crimson’ were similar in the field and in the high tunnel but lowest under the row
cover.
Tomato yields:
Tomatoes 2010 (5 plants per location)
Total yield (g)
Cultivar Field High tunnel Row cover
Rutgers 20,660 21,000 1,962
Cosmonaut 15,552 23,420 8,385
Both cultivars yielded most in the high tunnel, followed by the field. Plants under row covers pro-
duced far less than the other two locations.
Eggplant yields:
Eggplant 2010 (5 plants per location)
Total yield (g)
Cultivar Field High tunnel Row cover
Black Beauty 140 3,016 3,586
Turkish Orange 0 1,057 130
‘Turkish Orange’ did not yield much at any location. ‘Black Beauty’ grown under the row cover
and in the high tunnel far out-produced plants grown in the field. Grasshopper infestations were prob-
lematic, leading to lower field production.
7

8. 2009 Season-Extension Nutritional Analyses
Pepper nutritional analyses:
Total phenols were highest in both varieties under row covers, while total flavonoids were high-
est when grown in the high tunnel. Antioxidants, as measured by ORAC, were highest in the field for
‘King of the North’ and in the high tunnel for ‘Purple Beauty’.
8
Total Phenols and Flavonoids:
Season Extension Peppers 2009
Antioxidants:
Season Extension Peppers 2009
Variety and Location
Variety and Location

9. Tomato nutritional analyses:
Total phenols and total flavonoids were highest for both cultivars when grown in the field, while
highest antioxidant values were found when plants were grown under row covers.
9
Total Phenols and Flavonoids:
Season Extension Tomatoes 2009
Antioxidants:
Season Extension Tomatoes 2009
Variety and Location
Variety and Location

10. Eggplant nutritional analyses:
Total phenols were highest for both varieties when grown in the field. Total flavonoids were highest
in ‘Black Beauty’ when grown under the high tunnel and in ‘Turkish Orange’ in the field. Antioxidants
were highest when ‘Black’ was grown under row cover and in ‘Turkish Orange’ in the high tunnel.
‘Turkish Orange’ did not produce any fruit under the row covers so no nutritional data are available for
that test.
10
Total Phenols and Flavonoids:
Season Extension Eggplants 2009
Antioxidants:
Season Extension Eggplants 2009
Variety and Location
Variety and Location

11. 2010 Season-Extension Nutritional Analyses
Pepper nutritional analyses:
‘King Crimson’ produced highest total phenols under the high tunnel. Unfortunately, ‘King Crim-
son’ samples grown under row covers were unusable for analysis, so no antioxidant data are available.
Field-grown ‘California Wonder Orange’ had the highest total phenols of the three growing locations.
Total flavonoids were highest with ‘King Crimson’ in the field and ‘California Wonder Orange’ under
row covers. Antioxidants were highest in the field for ‘King Crimson’ and under row covers for Cali-
fornia Wonder Orange.
11
Total Phenols and Flavonoids:
Season Extension Peppers 2010
Antioxidants:
Season Extension Peppers 2010
Variety and Location
Variety and Location

12. Tomato nutritional analyses:
Highest total phenols appeared in row cover-grown ‘Rutgers’ and high tunnel-grown ‘Cos-
monaut’. Total flavonoids were highest in the field with both cultivars. Antioxidants were also
highest in field-grown plants of both cultivars.
Total Phenols and Flavonoids:
Season Extension Tomatoes 2010
Antioxidants:
Season Extension Tomatoes 2010
Variety and Location
Variety and Location
12

13. Eggplant nutritional analyses:
Total phenols and flavonoids varied by cultivar. Highest total phenols were found in high tunnel-
grown ‘Black Beauty’ and field-grown ‘Turkish Orange’. Highest total flavonoids were found in high
tunnel-grown ‘Black Beauty’ and ‘Turkish Orange’ under row cover. Field-grown plants of both variet-
ies had the highest antioxidant levels.
Total Phenols and Flavonoids:
Season Extension Eggplants 2010
Antioxidants:
Season Extension Eggplants 2010
Variety and Location
Variety and Location
13

14. Impacts and Recommendations
For producers wanting to grow under season-extension conditions, either under row covers or in a
high tunnel, of the varieties tested, suggestions would be ‘King of the North’ and ‘California Wonder
Orange’ peppers and ‘Rutgers’ and ‘Cosmonaut’ tomatoes. Eggplant varieties cannot be recommended
due to poor production both years.
From the 2009 season-extension studies, of the varieties tested, those somewhat nutritionally su-
perior would be ‘Purple Beauty’ pepper and either ‘Rutgers’ or ‘Cosmonaut’ tomato (almost the same
under row cover and high tunnel). From 2010 data, ‘California Wonder Orange’ pepper and ‘Cosmo-
naut’ tomato would be suggested. Again, eggplants cannot be recommended.
Some may wonder how late the season was actually extended under the high tunnel and the row
cover in both years.
Last Harvest Tomato Eggplant Pepper
2009 High tunnel October 6 September 10 October 6
Row cover October 6 October 6 October 6
Field September 8 September 10 September 10
2010 High tunnel October 17 September 23 September 23
Row cover September 23 September 23 August 26
Field September 10 September 10 September 10
It appears that the high tunnel and row cover extended the growing season about a month over
the field in 2009. In 2010, growing under the high tunnel extended the harvest about five weeks over
the field for tomato, two weeks
for eggplant, and two to three
weeks for pepper. Using season-
extension systems can increase
the growing season; however, it
is not clear there was any impact
on flavonoids, phenols, or anti-
oxidants. Field-grown produce
tended to show higher antioxi-
dant activity, while phenols and
flavonoids were more dependent
on plant species. To determine
real differences, further research
will need to be conducted using
a larger selection of varieties
as well as a larger numbers of
plants.
14

15. References
Cleveland Clinic. 2011. Heart-health benefits of chocolate unveiled.
http://my.clevelandclinic.org/heart/prevention/nutrition/chocolate.aspx
Accessed June 22, 2011.
Hollman, P.C.H. 2001. Evidence for health benefits of plant phenols: local or systemic effects? Journal
of the Science of Food and Agriculture. 81(9).
http://onlinelibrary.wiley.com/doi/10.1002/jsfa.900/pdf
Accessed June 22, 2011.
Nutrient Data Laboratory. 2007. Oxygen radical absorbance capacity (ORAC) of selected foods –
2007.
http://www.ars.usda.gov/sp2userfiles/place/12354500/data/orac/orac07.pdf
Accessed June 22, 2011.
Patel, J.M. 2008. A review of potential health benefits of flavonoids. Lethbridge Undergraduate Re-
search Journal. 3(2).
http://www.lurj.org/article.php/vol3n2/flavonoids.xml
Accessed June 22, 2011.
15